Canon G9 X has a 20.0MP 1" (13.2 x 8.8 mm ) sized BSI-CMOS sensor and features DIGIC 6 processor. On the other hand, Leica X Vario has a 16.0MP APS-C (23.6 x 15.8 mm ) sized CMOS sensor .
Below you can see the G9 X and X Vario sensor size comparison.
As seen above, Leica X Vario has a 3.2x Larger sensor area than Canon G9 X. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.
DxOMark Sensor Scores
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. It scores camera sensors for color depth (DXO Portrait), dynamic range (DXO Landscape) and low-light sensitivity (DXO Sports), and also gives them an overall score. Canon G9 X and Leica X Vario sensors have been tested by DxO and the results show that X Vario has a better overall score of 78, 15 points higher compared to G9 X's score of 63.